District Court Cannot Rely Solely on PTO’s Determinations to Find Patent Not Invalid

In Exmark Manufacturing Co. v. Briggs & Stratton Power Products Group, No. 2016-2197 (Fed. Cir. Jan. 12, 2018), the Federal Circuit vacated the district court’s grant of summary judgment that Exmark’s asserted patent was neither obvious nor anticipated.

Exmark sued Briggs, alleging infringement of Exmark’s lawn mower patent. Briggs filed two reexaminations at the PTO and the PTO upheld the patent’s validity. Exmark then filed a summary judgment motion in district court that the patent was not anticipated or obvious based on the PTO’s decisions involving the same prior art. The district court granted Exmark’s motion based solely on the outcome of these reexaminations. After trial, Briggs appealed this and other determinations.

The Federal Circuit vacated, finding the district court erred by relying solely on the PTO’s reexamination decisions. While acknowledging that the district court claimed only to afford the reexaminations “some, though not determinative, weight,” the court found no other evidence cited in support of the district court’s summary judgment decision. The court stressed that, regardless of what evidence was before the PTO during reexamination, district courts are obliged to arrive at their own conclusions regarding a patent’s validity. The court also noted that the district court disagreed with parts of the PTO’s construction, which suggested that Briggs might be able to show invalidity to the extent the district court’s construction was broader than the PTO.